A rare and eerie weather phenomenon shocked beachgoers in Portugal on Sunday, as a massive cloud resembling a tsunami swept across the sky — and quickly went viral online.
In the video, which has been widely shared on social media, the cloud appears as a giant wall, creating the illusion that it’s about to crash down onto the beach like an enormous wave.
Cloud Tsunami Sweeps Over Three Portuguese Cities
— NEXTA (@nexta_tv) June 30, 2025
A rare atmospheric phenomenon rolled across Portugal — a giant “roll cloud” resembling a tsunami in the sky. It was spotted in three coastal cities.
These clouds form due to sea breezes and appear as a long, horizontal mass… pic.twitter.com/H3KQeXB58p
According to international media outlets, this mesmerizing scene was caused by a rare meteorological event known as a roll cloud.
These clouds form due to the interaction of air masses with contrasting temperatures, often combined with sea breezes. The result is a tubular-shaped cloud that rolls horizontally across the sky — mimicking the appearance of a giant ocean wave, though it is not related to tsunamis.
As the cloud formation approached the coastline, strong winds suddenly struck the beaches, catching swimmers and sunbathers by surprise.
Ask me anything
Explore related questions
